Ultrasonic transducers are used with percutaneous or transurethral surgical instruments that ablate blood clots, de-bulk calculi, drill/core bone, or the like. Ultra-sonic transducers operate in the range of 18 kilohertz and above. Research has determined that prior art ultrasonic transducers perform at less than optimal levels. Energy is lost as it travels down the ultrasonic waveguide component of these transducers affecting the performance efficiency of the transducers. Substandard performance creates a negative economic impact on sales of ultrasonic transducers because they do not stand up to the standards of users who expect certain levels of performance during surgical procedures. It has been found that the position of the stop on the ultrasonic waveguide greatly affects the performance of the ultrasonic transducer. Moreover, the shape, position, and movement of shock-pulsing masses also affect the performance of the ultrasonic transducer. What is presented are new arrangements of the ultrasonic waveguide and ultrasonic transducer as well as variations of shock-pulsing masses, each of which facilitate maximizing performance of the ultrasonic transducer.